radioactive lenses

If radioactivity was an issue with these lenses, don't you think it would effect the film itself? - Especially if you left a roll in your camera for a while - one, two, six months, with the radioactive lens on? That said, it's suspected that someone left a 50/1.4 Tak (outstanding lens, btw - and cheeeep) in a fish tank in Tokyo that contained a pet turtle. The result? Gamera!
 
Hi George

Hi George

Maybe this link will answer some questions: http://www.hps.org/publicinformation/ate/q941.html

Here's an interesting question to ponder, what if an astronaut or Concorde crew member (if they come back), also likes to wear his Leica with '52 hot lens 24x7??

George S. said:
Two thoughts/questions...

If flying exposes you to more radiation than these lenses do,
a: shouldn't airline pilots and flight attendants be dying early deaths from cancers? I don't see that.
and b: hence there should be no worries with regard to the lenses.

Wouldn't an extreme example of a radioactive lens left mounted on a film camera loaded with film, fog that film?
Click to expand...
 
It is my understanding that people who do work in slightly higher radiation environments do have a slightly higher mortality rate from cancers and other radiation induced diseases.

Newer medical technologies generally use less and less radiation per exposure dose.

Dentists used to stay in the room with you, and even sometimes held the film in place with their finger. Today Xrays sources are collimated and I am not sure how the dose is adjusted for digital sensors.

OTOH, some historically famous people died because they were so fearful of Xrays that they remained undiagnosed of treatable disease.

Have not asked technicians recently if they still wear film badges, or any other form of monitoring device. Am probably to get some sort of xray this year, may ask.

Am pretty sure if you suspect your hot lens of danger, your local university may well have a kind soul in the Physics Dept. or Chemistry, who may check it out for you.

A particularly good source, albeit a very busy one, is Jearl Walker Professor of Physics at Cleveland State University, who now authors the well known and most commonly, Halliday and Resnick (Now I believe Haliday, Resnick, and Walker), and former editor of the Physics of Everyday Phenomena in Scientific American. Jearl is a former instructor of mine and colleague at CSU.

Am pretty sure if he found it of general interest, he might investigate and post to his site.

I believe you can find him also on Facebook and he has a website, Flying Circus of Physics, named for the book he authored and a course he originated at CSU.

Interesting person to bookmark.

Regards, John
 
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It's expensive, but not crazy so.

This chemical uses depleted uranium. It has very low level alpha emission radioactivity. If I hold the geiger counter directly over the yellow powder, it clicks to be sure, but once dissolved in solution or on a toned print, I get no reading above the background level at all.
 
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Very true. Uranium is very toxic because even though alpha particles can be stopped by a few sheets of paper, once the emitting substance is inside you, it has nothing to get through to get at you.

I forgot to say: DON'T TRY THIS AT HOME.
 
Great thread only just picked it up. Slightly off topic, I have a lovely SLR Nikkor 35mm f1.4 with thorium glass. Being a RPA I have access to a number of radiation instruments to measure the emitted radiation (I did it the first time I had the lens 3uSv/h gamma off front and rear elements I think). If people are interest I will remeasure and post the results. Next time I will use a Ion chamber to get beta gamma surface dose rates. You may wish to know were the lens (and camera) is currently stored, its in the next bedroom on the extreme side of the room. Pity I do not have a radon gas monitor to measure the release (if measurable) from the glass.

With gamma radiation the inverse square law applies. double the distance the dose rate goes down to 1/4.

I would be more concerned with a granite kitchen work top in the house than using a thoriated lens on a camera.
 
kram said:
Great thread only just picked it up. Slightly off topic, I have a lovely SLR Nikkor 35mm f1.4 with thorium glass. Being a RPA I have access to a number of radiation instruments to measure the emitted radiation (I did it the first time I had the lens 3uSv/h gamma off front and rear elements I think). If people are interest I will remeasure and post the results. Next time I will use a Ion chamber to get beta gamma surface dose rates. You may wish to know were the lens (and camera) is currently stored, its in the next bedroom on the extreme side of the room. Pity I do not have a radon gas monitor to measure the release (if measurable) from the glass.

With gamma radiation the inverse square law applies. double the distance the dose rate goes down to 1/4.

I would be more concerned with a granite kitchen work top in the house than using a thoriated lens on a camera.
Click to expand...

And indeed a radon-filled cellar in an area with lots of granite (I'm a Cornishman).

But as I think I said earlier, I'd not store a cache of Aero Ektars under the bed.

Cheers,

R.
 
And indeed a radon-filled cellar in an area with lots of granite
Click to expand...
Ah! a ready made radon sump. Just stick a extractor fan in the cellar (to the outside of the house, not the kitchen😉) and you will be fine.

As an aside Roger, your book lead me to by a larger format camera (MPP VII), which in turn has lead me to buy my first new camera in 15 years...a 5x7.
 
kram said:
Ah! a ready made radon sump. Just stick a extractor fan in the cellar (to the outside of the house, not the kitchen😉) and you will be fine.

As an aside Roger, your book lead me to by a larger format camera (MPP VII), which in turn has lead me to buy my first new camera in 15 years...a 5x7.
Click to expand...

Sorry!

Fun, though, innit?

Cheers,

R.
 
Mr. Waker is still making the camera at the moment so I am getting things ready for the big day. Adox CHS 100 ordered, 5x7 dark slides purchased, orbital at the ready and 120mm wide angle(?) lens to start me off. Am I am itching to take a 5x7 photo of something which you would not consider using a large format camera for (but as you say it should be fun) - will have to use flash for a couple of the shots.
 
kram said:
Mr. Waker is still making the camera at the moment so I am getting things ready for the big day. Adox CHS 100 ordered, 5x7 dark slides purchased, orbital at the ready and 120mm wide angle(?) lens to start me off. Am I am itching to take a 5x7 photo of something which you would not consider using a large format camera for (but as you say it should be fun) - will have to use flash for a couple of the shots.
Click to expand...

The biggest problem I find with 5x7 is forgetting the amount of bellows extension in indoor shots, and underexposing.

I assume you mistyped 'Waker' for 'Walker'. Mike's cameras are really nice and very clever. I think you'll love it! Send hm my regards!

I use mostly 110mm, 210mm and 300mm on 5x7, plus the old 168 Dagor. The great thing is than in a contact print, everything is super sharp anyway.

Cheers,

R.
 
Roger, you are right about the typo. I think it is the right camera for my style of photography. Had a use of a John Nesibitt 5x7 camera, not for me (although I loved the craftsmanship of the wood work, not so the easy of folding it, and brass work).

Bact on subject, I plan to measure the gamma and beta gamma dose rate with a monitor which uses an ion chamber (in calibration!). Will post results.
 
Hi

Hi

Would be interesting to know exactly where you measure. I plan to measure in uSv/hr at the front of the lenses and back of the lenses and probably note where the highest readings are. My stuff is also calibrated, and certified.

An interesting data point, but variable to where one lives, etc., would be what the current background uSv/hr is where you reside.

kram said:
Roger, you are right about the typo. I think it is the right camera for my style of photography. Had a use of a John Nesibitt 5x7 camera, not for me (although I loved the craftsmanship of the wood work, not so the easy of folding it, and brass work).

Bact on subject, I plan to measure the gamma and beta gamma dose rate with a monitor which uses an ion chamber (in calibration!). Will post results.
Click to expand...
 
Here are the readings for an Nikkor-N (slr) 35mm f1.4 lens (serial No.35205*, does anyone know the age of this lens?).
Gamma reading taken with a NE Electra GM, averaged over 60 seconds (if a range is given it because three independent reading were taken) all readings in uSv/h. Note, the centre of the detector for the GM is 15mm below the instruments surface. Background dose rate 0.16-0.20.
Front of lens 3.6 -4.1, rear of lens 6.5-6.8, side of lens 3.5-3.6. Back of Nikon F camera with lens attached 1.4.
front of lens B+W Filter attached 3.3, no filter 3.5 (note GM positioned filter thickness away from from of lens ~3mm).
Camera on CCS small holdall dose rate on surface of holdall ranged from 0.5 to 1.0.

With a Mini SmartION no difference was detected with the Bea slide open or closed. Readings from smartION erratic🙁, background dose rate ~1.2 ( Instrument not suitable for these low dose rates - great at higher levels). Note the centre of the detector for the SmartION is 45mm below the instruments surface, no averaging fluctuating range given
Front 3.3-4.2
Side 3.1-3.7
Back 3.8-4.9
 
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